:`relativedelta.relativedelta` objects. rather than
    strings.

    :param s:
        A time zone string in ``TZ`` variable format. This can be a
        :class:`bytes` (2.x: :class:`str`), :class:`str` (2.x:
        :class:`unicode`) or a stream emitting unicode characters
        (e.g. :class:`StringIO`).

    :param posix_offset:
        Optional. If set to ``True``, interpret strings such as ``GMT+3`` or
        ``UTC+3`` as being 3 hours *behind* UTC rather than ahead, per the
        POSIX standard.

    .. caution::

        Prior to version 2.7.0, this function also supported time zones
        in the format:

            * ``EST5EDT,4,0,6,7200,10,0,26,7200,3600``
            * ``EST5EDT,4,1,0,7200,10,-1,0,7200,3600``

        This format is non-standard and has been deprecated; this function
        will raise a :class:`DeprecatedTZFormatWarning` until
        support is removed in a future version.

    .. _`GNU C Library: TZ Variable`:
        https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html
    Fc